The aim of this study was to describe the demography of centenarians in Denmark in the period 1775-1995. The prevalence of centenarians increased from about 1-2 pr. million in the last half of the 1800s to about 80 pr. million in 1995, especially among women since 1950 leading to a female/male-ratio of three to one. A total of 4292 centenarian deaths were found reported in different sources. The number of reported centenarian deaths was found to be much higher in the first half than in the last half of the 1800s, especially among men and among 105+ year-old: A through examination of 275 reported centenarian deaths on the Island of Funen from before 1900 indicates that this most plausibly was due to age-exaggeration and lack of validation of the reported ages before 1850. This was supported by a backward extrapolation of regression estimates based on the reported number in the period 1870-1925, which showed a much lower estimated number of centenarians than reported in the first half of the 1800s, indicating an emergence of centenarians after 1780. The probability of becoming a centenarian only first increased substantially for cohorts born after 1860. The reduction of mortality among the oldest old in the last decades has created a new generation of very old people. The proportion of centenarians can therefore be considered as an indicator of earlier changes in lifestyle and care for elderly. Udgivelsesdato: 1996-Dec-16